Primer composition



Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE PRIMER COMPOSITION Gordon H. Chambers,

to Foote Mineral Company, Philadelphia,

Philadelphia, Pa., assignor a corporation oi Pennsylvania No Drawing. Application September 23, 1931, Serial N0. 584,725

13 Claims.

nated a primeris a part (or a charge) in 30 which ignition is thermally or electrothermally initiated, and by which an explosion is started that ultimately fires another charge by detonation. From these facts and the peculiar properties of zirconium just explained, its advantages in I5 igniter charges or primers for both types of devices' those percussively fired, and those thermally fired-may be in part appreciated. As an example of the use of zirconium in primers, I may instance its addition to an ordinary standard composition of mercury fulminate, ba-

rium nitrate, and antimony sulphide, preferably in such substantial proportions as 10 parts, say, of commercial zirconium powder to 100 parts of the total of the aforementioned ordinary primer ingredients, by weight. In such a primer-composition for ammunition, the mercury fulminate serves as a highly sensitive percussive combustion-initiator; the barium nitrate as an oxidizer, non-corrosive toward a gun barrel; and the antimony sulphide as a combustible or fuel,though less sensitive than zirconium. Wide variation of proportions is permissible, however: e. g., an addition of as little as 2% zirconium powder will give greater ignitibility to some primer mixtures; and it may, on the other hand, be used in much powder ignites larger proportions than more.

A further advantage of zirconium in primers or blasting caps is its agains such as 25% or it does not deteriorate in contact with moisture. Zirconium also resists the attack of many of the oxidizers and alkali compounds that are used in and percussion mixtures. For all of these reasons, it increases the life, efl'iciency, and reliability of priming and detonating compositions in which it is used.

' In the use of priming mixtures containing it, zirconium forms a heavy ash with some of the usual ingredients, such as barium nitrate, and

thus reduces or-eliminates the smoke from the primer. It also appears to form a protective coating (probably a thin layer of zirconium oxide) in gun barrels,.a property which may give it special value in a non-corrosive, non-mercuric primer.

It is to be observed that commercial zirconium metal powder as at present produced appears to contain a substantial proportion of impurityprobably a suboxide or hydride of zirconiumwhose exact character and effect on the properties of the powder have never been definitely determined. It is possible, of course, that various advantages of zirconium .for my purposes (as hereinbefore set forth) are either diminished or enhanced by such "suboxide" or other impurity or dependent on its presence. Accordingly, the addition or substitution of such suboxide? to or for zirconium powder is within the scope-of my invention in its broader aspects, as well as the use of zirconium without the presence of the suboxide.

Having thus described my invention, I claim:

1. A percussively fired igniter charge for an explosive charge, comprising zirconium.

2. A percussively exploded composition comprising zirconium.

3. An ammunition priming mixture containing zirconium, an oxidizer, and a combustion initiator.

4. An ammunition priming mixture containing zirconium, a non-corrosive oxidizer, and a suitable combustion initiator.

5. An ammunition priming mixture containing zirconium, a second fuel ingredient, a non-corrosive oxidizing ingredient, and a combustion initiator.

6. An ammunition priming mixture containing zirconium, and barium nitrate.

'7. An ammunition priming mixture containing zirconium, barium nitrate, and mercury fu1mi- 5 nate.

8. An ammunition priming mixture containing zirconium, antimony sulphide, a suitable oxidizer, and a suitable combustion initiator.

9. An ammunition priming mixture containing 1 zirconium as fuel.

10. An ammunition priming mixture containing metallic zirconium and a non-corrosive oxidizer.

11. A non-corrosive priming mixture comprising a nitrate adapted to serve as an oxidizing agent without corrosive tendencies toward a gun barrel, and zirconium as a fuel.

12. An ammunition priming mixture containing a combustion initiator, an oxidizer, a fuel, and a small quantity of zirconium.

13. A non-corrosive priming mixture comprising a combustion initiator, a nitrate adapted to serve as an oxidizing agent without corrosive tendencies toward a gun barrel, and metallic zirconium as a fuel.

GORDON H. CHAMBERS. 

